In the related art, there has been known a substrate processing apparatus in which in a state where a substrate storage is loaded on a substrate storage temporary shelf, an inert gas is supplied/discharged into/from the substrate storage (see, e.g., Japanese Patent Laid-Open Publication No. 2000-340641). The substrate processing apparatus disclosed in Japanese Patent Laid-Open Publication No. 2000-340641 is configured such that an inert gas inlet port and an atmosphere outlet port for flowing out atmosphere within the substrate storage are formed in a bottom plate of the closed-type substrate storage, an inert gas supply port and an atmosphere discharge port for discharging the atmosphere within the substrate storage are formed on the shelf of the substrate storage, the inert gas inlet port and the inert gas supply port may be fitted to each other, and the atmosphere outlet port and the atmosphere discharge port for flowing out and may be fitted to each other. Then, in the configuration of the substrate processing apparatus, an inert gas supply source is connected to the inert gas supply port, an open/close valve is provided in each of the inert gas inlet port, and the atmosphere outlet port, a solenoid valve is provided in a pipe between the inert gas supply port and the inert gas supply source, and each of the open/close valves and the solenoid valve is opened when the substrate storage is placed on the substrate storage temporary shelf.
According to Japanese Patent Laid-Open Publication No. 2000-340641, it is described that through the above-described configuration, since an inert gas is supplied into the substrate storage in a state where the substrate storage is loaded on the substrate storage temporary shelf, it is possible to suppress a natural oxide film from being generated on a substrate in a state where the substrate storage is stored in the substrate processing apparatus, to omit a step of filling the inert gas into the substrate storage during of the conveyance of the substrate storage, which has conventionally been performed to prevent natural oxidation of the substrate, and to shorten a carry-in/-out time of the substrate storage.